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New Product: Carl Zeiss SMT’s Starlith 1900i pushes limits of catadioptric lenses |
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Sep 25, 2006 at 10:35 AM |
 Product Briefing Outline: Carl Zeiss SMT has announced the development of its lithography optical system, ‘Starlith' 1900i. The new system has a numerical aperture (NA) of 1.35, the highest NA currently designed, that will be used for volume chip production at 40nm half-pitch node. The system will be part of ASML's new ‘TWINSCAN' XT:1900i immersion lithography tool that will begin shipments in 2007.
Problem: In order to increase the NA much beyond .93, traditional lens
designs required highly complex and large lens arrangements that would
be difficult to build and cost preventative. To boost NA further, water
is used between the final lens and the wafer. This allows catadioptric
lens configurations to be used closer to the refractive index of water
(1.44). The higher NA improves the ability to image feature sizes below
50nm.
Solution: The proprietary ‘Catadioptric Inline Multi Mirror Design' is
designed to allow standard fitment within existing ASML lithography
platforms, using an even number of mirrors as part of the catadioptric
lens assembly, resulting in no image flip and the use of conventional
mask technology. Essential for printing 40nm features with large
process windows is the inclusion of a new illuminator ‘AERIAL XP.'
Special emphasis has been placed on polarization control in the
illumination system. The wide variety of possible illumination settings
enables chip manufacturers to fine-tune optimized illumination
conditions matching the relevant device features (mask structure and
mask type).
Applications: ASML ‘TWINSCAN' XT:1900i immersion lithography tool.
Platform: The ‘Starlith' 1900i lens is based on the proprietary
"Catadioptric Inline Multi Mirror Design", enabling a compact single
barrel design. Since an even number of mirrors is used, there is no
image flip, and the same masks as in all other system can be used. The
system will be part of ASML's new ‘TWINSCAN' XT:1900i immersion
lithography tool.
Availability: Mid-2007 onwards.
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Lithography 
